NEW YORK — J.R. Ewing wouldn’t hesitate to cheat his fellow man. He also famously cheated death.

In the second-season finale of “Dallas” back in 1980, he was shot by an unknown assailant in his office and left for dead. But he recovered nicely, and the cliffhanger question that gripped the nation (Who shot J.R.?) was answered that November in an episode seen by 80 million viewers.

This time, J.R. won’t get off so easy. During the second season of TNT’s rebooted “Dallas,” J.R. cashes in his chips and goes to his reward ... wherever that may be.

Meanwhile, viewers, however braced they are for J.R.’s demise, will have to reckon with the loss of arguably TV’s greatest villain, and bid farewell to the actor who portrayed him so indelibly and also cheated death for years. Larry Hagman, who died of cancer at 81 the day after Thanksgiving, was diagnosed in 1992 with cirrhosis of the liver from a life of heavy drinking and, three years later, when a malignant tumor was discovered on his liver, successfully underwent a transplant.

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This double loss would be a burden for any show to bear. “Dallas,” returning at 9 p.m. Monday, comes fully loaded.

But all that comes later. With its two-hour season premiere, “Dallas” carries on in familiar fashion, with the expected two-timing, squabbles, a kidnapping revealed, a stolen identity and assorted other mischief.

And never fear: J.R., though visibly frail, continues his reign as a scheming oilman and rascally Ewing patriarch.

“I came over to deliver some muffins to the pretty little secretaries,” he announces on making an unannounced visit to Ewing Energies headquarters before he laments, “Who could have guessed so many would turn out to be MEN? Where’s the sport in THAT?”

In another scene, J.R. shares sly counsel with his son, John Ross, on double-crossing other members of the family: “Love, hate, jealousy: Mix ‘em up and they make a mean martini. And when we take over Ewing Energies, you’ll slake your thirst — with a twist!”

The new “Dallas,” which debuted last June, is stocked with a troupe of young regulars (including Josh Henderson, who plays John Ross), as well as veterans of the original CBS series, notably Gray and Patrick Duffy as J.R.’s ever-upright brother, Bobby. J.R. will appear in a minimum of five or as many as seven of the season’s episodes before he meets his fate.

After that, can “Dallas” survive the dual deaths of its central character and legendary star?

“Larry being gone doesn’t eliminate the influence of the character of J.R.,” Duffy pointed out. Who knows what land mines J.R. will have left behind? “We can find business deals he did or schemes he started that now are coming home to roost, and they can turn up for years to come.”

“Whatever will happen on the show, we will be talking about J.R. Ewing and he will have done things that have a ripple effect,” Gray agreed. “He will always be there.”

“There’s a lot of driving forces on the show — not just J.R.,” added “Dallas” executive producer Cynthia Cidre, who, interviewed by phone a couple of weeks ago, was parked outside a posh Dallas social club where the wake for J.R. was about to be filmed.

She said this season she tried to use Hagman sparingly.

“He was the most delightful man and a total professional,” she said, “but he wasn’t well and we didn’t want to overtax him.”

Now, with his passing, “we want to give J.R., and Larry, the proper send-off.”

But she insisted there had been no contingency plan for how to plot J.R.’s demise in the event Hagman died in mid-season.

“We didn’t have a Plan B, on purpose,” said Cidre. “We just knew that we had Larry, so let’s use him, let’s enjoy him, and if something happens, we’ll scramble and fix it. I had great faith in the writers’ room. We knew the day might come and what we would do then: Figure it out.”

That day came in late November when she got a call from Duffy. “He told me, ‘Larry’s in the hospital and it isn’t good. He’s saying goodbye.’ In 24 hours we had fixed one of the scripts. We had two more scripts that had to be adjusted, and then this episode we’re shooting now, the Goodbye Episode.”

Roughly 85 percent of the season’s story line remains intact, she said, supplemented by the death of J.R. and the mystery surrounding it: Who Killed J.R.?

“The mystery has all the machinations of a great J.R. business deal, as opposed to a whodunit,” said Duffy. “Cynthia constructed a really interesting plot, of which I know Bobby’s portion” — including whodunit — “but I don’t know other stuff.”

“We all know, up to a point,” Gray said. “But they’ve got secret pages that we’ve not seen.”

“I hope that we have come up with something really wonderful and enticing,” said Cidre, “and by the time you’re done watching episode 208, which I call the Funeral Episode, I hope you’re saying, ‘Omigod, I didn’t see that coming, and I can’t wait to watch the rest of the season.”’

The mystery, she said, will continue through episode 15, “with a giant, delightful, delicious climax in the season finale.”

To get there, shooting continues until April on the Dallas set, where, even two months after Hagman’s passing, “I’m lonely because my best friend isn’t there to play with,” Duffy said. “I was with him from 1978 until his final hours in the hospital. But I have no regrets. Every day I think of him and smile.”

“I keep expecting him to walk in the door,” Gray said. “He’s so missed. But his presence is everywhere!”